1. Field of the Invention
The present invention relates to battery condition monitoring devices for monitoring various types of conditions of a high voltage battery which acts as a main driving power source mounted to hybrid vehicles and electric vehicles.
2. Description of the Related Art
Various types of battery condition monitoring devices have been proposed and used in vehicles such as hybrid vehicles and electric vehicles. Such a battery condition monitoring device monitors conditions of a battery capable of supplying electric power to a vehicle driving system of an electric vehicle. In more detail, the battery condition monitoring device detects various conditions of the battery such as a voltage, a temperature, etc. of the battery mounted to the electric vehicle. When detecting an occurrence of an abnormal condition such as a battery fault of the battery, the battery condition monitoring device disconnects the battery from the vehicle driving system in order to stop the supply of the electric power of the battery to the vehicle driving system mounted on the electric vehicle. For example, Japanese patent laid open publication No. JP 2006-20380 discloses a conventional battery condition monitoring device having the above structure.
However, the conventional battery condition monitoring device disclosed in JP 2006-20380 previously described has a drawback in that the structure cannot drive the vehicle driving system such as an electric motor when a main control circuit in the battery condition monitoring device malfunctions, but the battery is in a normal condition without any trouble because the conventional battery condition monitoring device has the structure in which the power supply from the battery to the sub-control section is inhibited when the main control section is in an abnormal condition. Accordingly, the conventional battery condition monitoring device having the structure previously described has a low malfunction resistance.